The present invention generally relates to a display apparatus for image reproduction, character display or the like using a cathode-ray tube (hereinafter referred to as a CRT).
An inline self-convergence CRT system (hereinafter referred to as a non-uniformmagnetic system) in a television field causes considerable resolution deterioration when electronic beams are deflected by deflection yokes. The deterioration in picture scenes and their circumferences is significant. Various proposals have been introduced to solve the problem. A dynamic focusing system is available to remove the difference in focusing, for example, between the central portion of the picture scene and the circumference portion. In order to remove the deflection distortion in the circumference, an electromagnetic correcting system is disclosed in Japanese Laid-Open Patent publication No. 57-84683, and an electrostatic system is represented by a DAF system.
Exceptional resolution deterioration is caused in the deflection of the electron beams in a wide range even if the yoke is a uniform magnetic field deflection yoke.
The above described Japanese Laid-Open Patent publication No. 57-84683 is complicated in construction, composition, and has a high cost. The electrostatic system represented by the DAF system is high in applied voltage, with problems in terms of reliability and cost.